ipv4: ip_check_defrag should correctly check return value of skb_copy_bits

skb_copy_bits() returns zero on success and negative value on error,
so it is needed to invert the condition in ip_check_defrag().

Fixes: 1bf3751ec90c ("ipv4: ip_check_defrag must not modify skb before unsharing")
Signed-off-by: Alexander Drozdov <[email protected]>
Acked-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index e5b6d0ddcb5808f662ca0b1fd5863d63e6b54b83..2c8d98e728c09feea0ffe45adf8b9b2470078c43 100644 (file)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -664,7 +664,7 @@ struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
        if (skb->protocol != htons(ETH_P_IP))
                return skb;
 
-       if (!skb_copy_bits(skb, 0, &iph, sizeof(iph)))
+       if (skb_copy_bits(skb, 0, &iph, sizeof(iph)) < 0)
                return skb;
 
        if (iph.ihl < 5 || iph.version != 4)